Remove spaces using .replace method

I'm trying to replace multiple whitespaces with single ones in a Google Doc with a script. But unfortunately the provided solution to this question isn't working for me. As you can see, I tried several alternatives but can not figure out how to do it right. Any ideas?

function searchAndReplace() {
  var body = DocumentApp.getActiveDocument()
      .getBody();
  body.replaceText(/\s{2,}/,' ');
  body.replaceText(/\s/g, " ") ;
  body.replaceText("/\s/"," ");
  body.replaceText('/\s{2,}/',' ');
}

Try:

function searchAndReplace() {
  var body = DocumentApp.getActiveDocument().getBody();
  body.editAsText().replaceText('\\s*', ' ');
}

UPDATE

One option is:

function getCorrections() {
  var _getCorrections = 0,
      text = DocumentApp.getActiveDocument().getBody().getText(),
      regexp = /\s+/g,
      matchesCorrections = text.match(regexp);

  if (matchesCorrections) {
    _getCorrections = matchesCorrections.reduce(function(previousValue,
                                                         currentValue) {
      return previousValue + currentValue.length - 1;
    }, 0);
  }

  return _getCorrections;
}